The Whim Creek Copper Project is a wholly owned and fully engineered project, located near the North West Highway, midway between Karratha and Port Hedland in Western Australia.
In 2003 the Straits Board approved the development of Whim Creek, and construction activities commenced in the first half of 2004. First copper was produced at Whim Creek in June 2005. Mining commenced 12 months later at the nearby Mons Cupri deposit.
In August 2009, Straits Resources announced its intention to sell the Whim Creek project to VentureX Resources. The deal was finalised on 1 February 2010 and included the sale of the mine along with its related exploration tenements besides the Salt Creek and Balla Balla copper-zinc projects. Straits Resources holds 19.9% of VentureX Resources.
In March 2010, Venturex began drilling at the site. Venturex is also designing additional drill campaigns to target the lateral and depth extensions at Balla Balla.
The Whim Creek belt contains outcropping VHMS style mineralisation that has been oxidised at surface. The tenements also cover extensions of the Mallina shear that hosts the Indee gold deposit and equivalent structures such as the Scholl shear to the north. The Scholl shear contains the Sherlock Nickel deposit and the Balla Balla Vanadium deposit along strike. Geochemical sampling is planned to define these targets.
In its 2008 annual report, Straits Resources said that it had found a new sulphide lense close to the Salt Creek project. “The Balla Balla lens in particular looks to have excellent potential to increase the resource base of the sulphide project,” the company said.
Geology and reserves
The Whim Creek project is made up of two deposits: Whim Creek and Mons Cupri within about 6km of each other.
Whim Creek is a shallowly dipping deposit, with remobilised leachable copper mineralisation of malachite and minor azurite. The Mons Cupri deposit is a volcanogenic massive sulphide deposit with shallow dipping mineralised horizons in the Mons Cupri hill. Mineralisation comprises secondary malachite with a stock work/stringer zone.
The Mons Cupri and Whim Creek deposits contain a chalcopyrite hosted resource at depth with associated zinc and silver. At the Salt Creek project 16km from Whim Creek a resource of 952,000t at 9.3% Zn, 0.7% Cu and 100 g/t Ag has been defined with the strong potential to increase this resource.
For its 2009 annual report, Straits Resources stated that Whim Creek had measured resources of 7,110kt graded at 0.3% Cu and proven ore reserves of 6,970kt graded at 0.2Cu. Proven reserves of sulphides stood at 1,760kt while measured resources of 3,666kt have been estimated.
The project has been developed by the open pit mining of two ore bodies, firstly the Whim Creek deposit, followed by Mons Cupri deposit approximately one year apart. Oxide copper ore is trucked 2.5km to a processing facility located midway between the two ore bodies
Processing is by heap leach, solvent extraction and electrowinning. The processing facility comprises a new crushing plant, agglomerator and overland conveyor – radial stacker arrangement.
Whim Creek produced 10,089t of copper cathode in 2009.
Poor crushing and stacking performance, has been an ongoing concern at Whim Creek. After a review of its options, the company decided to shut down the site crusher, replacing it with a pair of mobile contract crusher units.